Prior to this invention it has been the practice to employ electric initiators to ignite an explosive composition. Electric initiators generally function by heating a bridge wire in contact with a thermally initiable explosive. In an alternate form the bridge wire is replaced by a conductive explosive mix, which consists of a non-electrically conducting explosive powder mixed with a nonexplosive electrically conducting powder. Powdered metals or carbon have been employed for the conductive component of the mixtures while both common primary and secondary explosives have served as the explosive component. Such conductive mixes are placed between electrical terminals or electrodes. Current between the electrodes flows from one conductive particle to another through a series of contact points. Many of such paths form a complex parallel series network but one such path usually has a lower resistance than others so that the current tends to concentrate and the heat tends to concentrate at the contact points. The degree of concentration, and hence the relationship between temperature and electrical input, is dependent on particle size and shape, composition, uniformity of the mixture, loading density and electrode spacing and configuration. For this reason the fabrication of conductive mixes of specified electrical and firing characteristics has been difficult.